Aminoazetidinoneacetic acid esters

ABSTRACT

AND PROCESS FOR THEIR PREPARATION IN WHICH A PENICILLIN ESTER IS REACTED WITH A SOURCE OF POSITIVE HALOGEN TO SELECTIVELY OPEN THE THIAZOLIDINE NUCLEUS OF THE Novel beta-lactam compounds of the formula

United States Patent [191 Kukolja [111 3,860,577 51 Jan. 14, 1975 lAMINOAZETIDINONEACETIC ACID ESTERS [75] Inventor:

[73] Assignee: Eli Lilly and Company, Indianapolis,

Ind.

July 20, i972 Stjepan Kukolja, Indianapolis, Ind.

[22] Filed:

- 21 Appl. No.: 273,550

Related U.S. Application Data [62] Division of Ser. No. 148,129, May 28,l97l,

abandoned.

[52} US. Cl. 260/239 A, 260/239.l, 260/243 C,

260/308 B, 260/326 N, 260/326 S, 260/326.37 [51] Int. Cl.v C07d 25/02,C07d 27/10, C07d 27/52 [58] Field of Search 260/326 N, 326.37, 239 A[56] References Cited UNITED STATES PATENTS 3,799,938 3/1974 Heusler260/239 A Primary ExaminerAlton D. Rollins Assistant Examiner-Mark L.Berch v Attorney, Agent, or Firm william C. Martens, Jr.;

7 Everet F. Smith ABSTRACT Novel beta-lactam compounds of the formula ICH3 1 Claim, No Drawings AMINOAZETIDINONEACETIC ACID ESTERS COOH LN/\CH1 1 l wherein R and/or R represent hydrogen or a variety of organicradicals, particularly acyl groups as exemplified by hundreds ofexamples in the prior art. For example, one of the better knownpenicillins is penicillin V, or phenoxymethyl penicillin, which is knownto have the structure A somewhat more recent discovery is thecephalosporins, a class of antibiotics which are related from thestandpoint of chemical structure to the penicillin compounds described.The cephalosporins may be represented by COOH wherein R is preferably anacyl group and R" can be a number of groups including hydrogen, acetoxy,N- pyridino, etc. as described by the prior art.

it will be seen from the foregoing that both the penicillins and thecephalosporins contain a beta-lactam nucleus. It has therefore beenpostulated that the betalactam nucleus is of considerable importance inproviding antibiotic or anti-bacterial activity.

It is known[see Sheehan, The Synthetic Penicillins in MolecularModification in Drug Design, pp. 22-23, American Chemical Society(1964)] that the thiazolidine ring of the penicillin nucleus can beopened by the successive use of tertiary butylhypochloride and triethylamine, while leaving the beta-lactam intact. The product can then behydrogenated to form an azetidinone acetic acid. These reactions can beillustrated by reference to the following:

It has now been found that novel intermediates for use in thepreparation of novel antibacterials can be produced by selective openingof the thiazolidine ring of penicillin compounds between the sulfur(l-position) and the carbon in the 5-position with electrophilcs, whileleaving the B-lactam intact, to form ,B-lactam compounds having thefollowing structures:

(1001M (l' UUlia om o o \MMN /\l l on s on, 1tiN lip-1T: 1t.- (l\"a) lt:ow)

wherein R or R are hydrogen or an acyl group, or together with thenitrogen atom to which they are bonded define an imido group, R is theresidue of a earboxy protecting group and X and Y are substituentsintroduced by electrophilic agents.

It is accordingly an object of the present invention to prepare novel,B-lactam compounds of the type de scribed for use as intermediates inthe preparation of novel B-lactam derivatives having pharmacologicalactivity.

It is a related object of the invention to provide a process forselective opening of the thiazolidine ring of penicillin compounds whileleaving the B-lactam nucleus intact to form the sulfenyl intermediatesof this invention.

Another object is to provide a process for selective opening of thethiazolidine ring in penicillin compounds while leaving the B-lactamring system intact to form the olefinic intermediates.

It is yet another object of the present invention to prepare novelazetidine compounds having antimicrobial activity.

One concept of the present invention resides in a novel class offi-lactam compounds of the following formulas;

wherein R is an acyl group and R is hydrogen or R and R together withthe nitrogen atom to which they are bonded define an imido group, R is acarboxy protecting group, X is a group including chloro, bromo oralkanoyloxy containing 2 to 6 carbon atoms(e,g., acetoxy, propionoxy,butyryloxy, etc.) and Y is chloro, bromo, or a nitrogen heterocyclicsubstituent or succinimido.

R and/or R can be a variety of acyl groups, as exemplified by many ofsuch groups described by the prior art in Behrens et al. US. Pats. Nos.2,479,295, 2,479,297, 2,562,407 and 2,623,876.

Preferred acyl groups include groups of the formula QaCHm-L Q (V Ia)wherein n is zero or an integer from 1 to and Q represents hydrogen orone or more substituents ineluding C to C alkyl, (e.g., methyl, ethyl,propyl), C, to C1; alkoxy (e.g., methoxy, ethoxy, propoxy), nitro,halogen (e.g., chlorine, fluorine, bromine and iodine) andtrifluoromethyl; groups of the formula Q (VIb) wherein Q and n are asdefined above; groups of the formula wherein Q is as defined above; andgroups of the formula (VIc) trifluoromethylphenylacetyl,o-ethoxyphenylacetyl, pnitrophenylacetyl, phenylacetyl, phenylpropionyl,as well as a number of others.

Representative of acyl groups encompassed by (Vlb) are phenoxyacetyl,p-ethylphenoxypropionyl, 2,6-dimethoxyphenylacetyl, phenoxybutyryl,trifluoromethylphenoxypropionyl, bromophenoxyacetyl, as well as avariety of others. Illustrative of the acyl groups defined by (VIc)include phenoxy-a,a-dimethylacetyl, p-methoxyphen0xy-a,a-dimethylacetyl,etc.

Acyl groups defined by (Vld) above include acetyl, propionyl, butyryl,isobutyryl, tert-buty lacetyl, etc.

As indicated above, R is the residue of an esterforming alcohol. Sincethe ultitmate product formed from the compounds defined by (Va) and (Vb)above can be in the form of the acid, it is preferred that R be an esterresidue which is easily cleaved, such as by dilute aqueous base,trifluoroacetic acid or hydrogenation in the presence of a palladium orrhodium catalyst on a suitable carrier such as carbon, barium sulfate oralumina, or by reduction with zinc in an acid such as hydrochloric,acetic or formic acid. A variety of such ester residues are known forthis purpose. Preferred groups are those in which R is C to C alkyl suchas methyl, n-butyl, tert-butyl, etc., trichloroethyl, benzyl,p-nitrobenzyl, p-methoxybenzyl, benzhydryl, phthalimidomethyl, phenacyl,etc.

Illustrative of compounds of this concept of the invention include thefollowing:

Methyl 2-ch1oro-a-(l-chlorothio-l-methylethyl)-4 oxo-3-phthalimido-1-azetidineacetate Methyl 2-chloro-a-(l-bromothio-l-methylethyl) 4-oxo-3-phthalimidol -azetidineacetate 2,2,2-Trichl0roethyl 2-chloro-a-(l-chlorothiol methylethyl )-4-oxo-3-phthalimidol azetidineacetate Benzyl2-bromo-a-(l-bromothio-l-methylethyl)-4- oxo-3-phthalimido- 1-azetidineacetate Benzhydryl 2-chloro-a-( l-chlorothio lmethylethyl)-4-oxo-3-phenoxyacetamido-1- azetidineacetate2,2,2-Trichloroethyl 2-chloro-a-( l-chlorothiolmethylethyl)-4-oxo-3phenoxy-a,adimethylacetamido-l -azetidineacetatep-Nitrobenzyl 2-chloro-a-( l-chlorothiolmethylethyl)-4-oxo-3-phenylacetamido-1- azetidineacetate Methyl2-chloro-a-( l-chlorothio-l -methylethyl)-4-oxo-3-(2,6-dimethoxyphenyl-acetamido)-lazetidineacetate2,2,2-Trichloroethyl 2-bromo-d-,( l-bromothiol methylethyl)-4-oxo-3-acetamidol azetidineacetate p -Nitrobenzyl 2-chloro-a-(l-chlorothiol methylethyl )-4-oxo-3-butyrylamidol azetidineacetateBenzyl 2-chloro-a-( l-chlorothiol -methylethyl )-4- oxo-3-succinimido- 1-azetidineacetate Benzhydryl methylethyl)-4-oxo-3-(3-nitrophenoxypropionamido l -azetidineacetate Methyl2-bromo-a-(l-bromothio-1-methylethyl)-4-oxo-3-phenylpropionamido-l-azetidineacetate Methyl 2-acetoxy-a-(Lchlorothio-l-methylethyl)-4- oxo-3-phthalimidol -azetidineacetate2,2,2-Trichloroethyl 2-acetoxy-a-( l-bromothio-l2-chloro-a-(l-chlorothio-l- -2,2,2-Tric hloroethylmethylethyl)-4-oxo-3-phenoxyacetamido-lazetidineacetate p-Nitrobenzyl2-b utyryloxy-a-(l-chlorothio-lmethylethyl)-4-ox0-3-phenylpropionamido-1-azetidineacetate tert-Butyl 2-propionoxy-a( l-chlorothiolmethylethyl)-4-oxo-3-phenoxyacetamido-lazetidineacetate Methyl2-propionoxy-a-(l-chlorothio-lmcthylcthyl)-4-oxo-3-propionamido-lazctidincacctatcp-Methoxybenzyl 2-acetoxy-a-( l-bromothio-lmcthylcthyl)-4oxo-3-phthalimido-lazetidineacctate Methyl2-chloro-a-isopropylidcne-4-oxo-3- phthalimidol-azetidineacetate2,2,2-Trichloroethyl 2-chloro-a-isopropylidene-4-oxo-3-phthalimido-l-azetidineacetate Benzyl2-bromo-a-isopropylidene-4-oxo-3- phthalimido-l-azetidineacetateBenzhydryl 2-chloro-a-isopropylidene-4-oxo-3- phenoxyacet-amido-l-azetidineacetate 2-chloro-a-isopropylidene-4-oxo-3-phenoxy-a,a-dimethylacetamido-1- azetidineacetate2-bromo-a-isopropylidene-4- 65 Benzhydryl2-chloro-oz-isopropylidene-4-oxo-3-(3- nitrophenoxypropionamido l-azetidineacetate Methyl2-bromo-a-isopropylidene-4-oxo-3-phenylpropionamidol -azetidineacetateMethyl 2-acetoxy-a-isopropylidene-4-oxo-3- phthalimidol-azetidineacetate 2,2,2-Trichloroethyl 2-acetoxy-a-isopropylidene-4-oxo-3-phenoxyacetam idol -azetidineacetate p-Nitrobenzyl2-butyryloXy-a-isopropylidene-4-oxo-3-phenylpropionamido-l-azetidineacetate Another concept of the presentinvention resides in the opening of the thiazolidine ring of thepenicillin nucleus by reaction ofa 6-acylamido or 6-imido penicillinester with an electrophilic reagent. As used herein, the termelectrophilic reagent is intended to refer to and include those reagentswhich seek electrons.

In accordance with the preferred practice of the invention, use is madeof an electrophilic reagent which serves as a source of positive halogento effect selective cleavage or opening of the thiazolidine ring.Without limiting the present invention as to theory, it is believed thatthe electrophilic reagent attacks the free electron pair on the sulfuratom forming a sulfonium ion which, in turn, causes cleavage in the ringin accordance with 25 the following mechanism.

(XIII) cis or trans isomer (XI V) those skilled in the art that, whilethe foregoing mechanism has been exemplified using a positive chlorineatom from the electrophilic reagent in the preparation of the novelcompounds of this invention, other electrophilic reagents can similarlybe employed.

As indicated above, the electrophilic reagent employed in the practiceof the process of this invention is preferably formed of anelectrophilic component X, a source of positive halogen, and anucleophilic component Y. As used herein, the term source of positivehalogen" is intended to refer to and include any source of X,*, whereinX, is chlorine or bromine. A wide variety of halogenating agents areknown to those skilled in the art as supplying positive halogen and canbe used in the practice in the invention. Representative of suitablehalogenating agents are the elemental halogens, such as chlorine andbromine, sulfuryl chloride, sulfuryl bromide, N-halogeno amides andimides, such as N- chlorosuccinimide, N-bromosuccinimide, N,N- dibromohydantoins and organic hypohalide and particularly the alkanoylhypohalides, such as acetyl hypochloride, propionyl hypochloride,butyryl hypochloride, acetyl hypobromide, propionyl hypobromide, butyrylhypobromide, etc.

In addition, use can also be made of mixed halogen such as BrCl, Cll,BrI, etc. As can be appreciated by those skilled in the art, the use ofsuch mixed halogens provides a product containing mixed halogens.

The compounds described above wherein Y is nitrogen heterocyclicsubstituents are prepared using N- halo compounds as the source ofpositive halogen. Use of l-halo benzotriazole is illustrated below:

(XVII) out in the presence of an aprotic solvent, that is a solventwhich does not offer or accept protons. A wide variety of such solventsare known to those skilled in the art and can be used in accordance withthe practice of the invention. Representative of suitable solvents whichcan be used include dimethyl formamide, tetra hydrofuran, dioxane,aliphatic nitriles, such as acetoni-' trile, propionitrile, etc.;aromatic hyrocarbons and halogenated derivatives, such as benzene.toluene, dichlorobenzene. etc. as well as a number of others. It isfrequently preferred to make use of aliphatic halogenated hydrocarbonsolvents, such as methylene chloride, chloroform, bromoform, carbontetrachlorie, carbon tetrabromide, ethylene dichloride, ethylenedibromide, etc. since such halogenated solvents have little or notendency to react with the halogenating agent whereas some of thenon-halogenated solvents may not be completely inert, and thus consumehalogenating agent.

As will be appreciated by those skilled in the art, the alkanoylhypohalides can be generated in situ by reaction of halogen with analiphatic carboxylic acid. In this event, the solvent may be omitted, ifdesired.

The reaction temperature is not critical to the practice of the processof the invention, and depends somewhat on the nature of the side chainin the 6-position on the penicillin starting material. For example, whenuse is made of a 6-acylamido penicillin ester, best results are usuallyobtained with a reaction temperature within the range of -76 to 0C., andwith a 6-imido penicillin ester, at a reaction temperature within therange of 76 to 80C.

The relative proportions between the penicillin ester and the source ofpositive halogen are important in determining whetherthe reactiontherebetween results in the formation of a compound of the type definedby formula (Va) or of the type defined by formula (Vb). It has beenfound that when use is made of a mole ratio of source of positivehalogen to penicillin ester of up to about 1.5 the predominant productis a compound of the type defined by (Va). When use is made of a moleratio of source of positive halogen to penicillin ester in excess ofabout 1.5, and preferably 1.75 to 3.0 or higher, the predominant productis a compound of the type defined by formula (Vb).

As the penicillin ester starting material, use is preferable made of6-acylamido or 6-imido penicillin esters described above having theformula:

COORa (XVIII) Thus, penicillin V (i.e., phenoxymethyl penicillin) hasthe structure and can be named6-phenoxyacetamido-2,Z-dimethylpenam-3-carboxylic acid.

(XIX) Representative penicillin esters which can be used in the processof this invention include the following compounds.

p-Nitrobenzyl 6-phthalimido-2,2-dimethyl-penam-3- carboxylate2,2,2-Trichloroethyl penam-3-carboxylate 6-phthalimido-2,Z-dimethyl-Benzyl 6-succinimido-2,2-dimethyl-penam-3- carboxylate Methyl 6-(diphenoxyacetamido)-2,2-dimethylucts have the formula:

(tJOORs CH2 N A I CH3 R1N|\ R0 (XX) wherein R and R are as describedabove, R can be the residue of an ester group as defined by R above butis preferably hydrogen or an alkali metal cation and R is a grouphavingthe formula -SR; where R; is C to C alkyl, and'preferablyisopropyl (XXI) 6-(2,6-dimethoxybenzamido)- In addition, compounds (Vb)where X is Cl or Br can be reacted with an alkane thiol or disulfidecontaining 1 to 5 carbon atoms, an alkane'carboxylic acid containing 2to 6 carbon atoms or an alkane thiocarboxylic acid or their derivativescontaining 2 to 6 carbon atoms in the presence of reductant (e.g., zinc,etc.) to form the corresponding alkylthio, alkanoyloxy and alkanoylthioderivatives, respectively. These reactions can be illustrated by thefollowing:

where \V is -O or and R is C to C alkyl Compounds (XXIV) and (XXV) canthen be converted to the corresponding acids in accordance withprocedures well known to those in the art.

As indicated above, R and R in compounds (XX) are as described above,including an imido group when considered together with the nitrogen atomto which they are bonded. It has been found that compounds of the typedefined by (XX) where R and R together with the nitrogen atom to whichthey are bonded define an imido group, can be converted to thecorresponding amido by hydrolyzing the imido group with alkali at a pHof around 1 I for about 5 minutes at 0C. This reaction, using thephthalimido group for purposes of illustration, is as follows:

coon COOH ojN CH3 =N l-cm ona on; o C-N R5 pH 11 o CNH R6 0C. 0 COOH(XXVI) (XXVII) ([30 R3 C 00 R3 CH3 Positive CH: O N halogen O M N I i SI CH3 R F? X \Y 1 I X Compounds (Vb) prepared in this manner can also beconverted to the desired olefinic acid by the procedures described. I

Compounds which can be prepared in accordance with the foregoingconcepts include:

a-isoppropylidene-2-isopropylthio-4-oxo-3- phthalimido-l-azetidineaceticacid a-isopropylidene-2-isopropylthio-4-oxo-3-succinimido-l-azetidineacetic acidot-isopropylidene-2-acetylthio-succinimido-4-oxo-1- azetidineacetic acida-isopropylidene-3-(2'-carboxybenzamido)-4-oxo 2-propionylthio-l-azetidineacetic acida-isopropylidene-Z-acetylthi0-4-oxo-3-phthalimidol-azetidineacetic acida-isopropylidene-4-oxo-3-(3-carboxypropionamido)-2-propionylthio-lazctidineacctic acida-isopropylidene-2-acetylthio-4-oxo-3-(3'-carboxypropionamido)-l-azetidineacetic acid It will be understood thatthe present invention also contemplates the esters described above ofthe foregoing compounds, although the acids and salts are the preferredcompounds of this concept of the invention since the latter possess thedesired biological activity. The esters, as indicated above, can easilybe converted to the corresponding acid or salt in accordance with knownprocedures. The compounds of this invention are also useful in makingcompounds of the formula wherein W is O or S by dehydrohalogenation ofthe appropriate amide or thioamide with triethylamine. The correspondingthiazoline azetidinones are useful in the synthesis of cephalosporin andpenicillin antitiotics by methods described in U.S. Pat. No. 3,675,194and U.S. Pat. No. 3,681,380, and antimicrobial thiazoles described inU.S. Pat. No. 3,595,993.

In addition to their use as intermediates in the preparation of othercompounds of this invention, the compound of (Va) above are also usefulas intermediates in the synthesis of other bicyclic B-lactam compoundssuch as S-epi-penicillins, which have been found to be useful asinhibitors of B-lactamasc, as enzyme which destroys B-lactam antibioticsincluding. for example, cephalosporin C and cephaloridine (i.e., 7-(2'-thienylacetamido-3-pyridine-methyl-A3-cephem4- carboxylic acid), arelatively new cephalosporin antibiotic disclosed and claimed in U.S.Pat. No. 3,449,338 to Flynn.

By way of example, such 5-epi-penicillins can be prepared by subjectingcompounds (Va) to reductive cyclization using, for example, stannouschloride, as illus trated by the following equation:

COOR; COORJ CH; 0

N on, O N SnCl: H

CH3 S Rr-Nlll CH: Ri*N -o1 i S (Va) (XXIII) EXAMPLE 1 This exampledemonstrates the reaction of methyl6-phthalimido-2,2-dimethyl-penam-3-carboxylate with sulfuryl chloride.

A mixture of 3.24 g. of methyl 6-phthalimido-2,2-dimethyl-penam-3-carboxylate, ml. of carbon tetrachloride and 0.85 ml.of sulfuryl chloride is refluxed for one hour. Thereafter, the solventis evaporated, and the residue dissolved in benzene and chromatographedover silica gel using 1,600 ml. of benzene and l,600 ml. of a mixture ofbenzene and ethyl acetate (:5) as eluting solvents. Fractions of 20 ml.are collected at 15 minute intervals.

Fractions 23 to 28 provide 810 mg. of methyl 2- chloro-a-(1-chlorothio-l-methylethyl)-4-oxo-3- phthaIimido-l-azetidineacetate.This material is recrystallized from benzene. mp l58l60C.; ir (CHCl1800, 1785, 1750, and 1735 cm; nmr (CDCI 103.5(S, 6H); 232$, 3H);274.5(S,1H); 332.5 (d,lH,J=2Hz); 364(d,lH,J=2Hz) and 47l.5cps(S,4,ArI-I).

Anal. calcd. for C I-I Cl N O S: C, 47.34; H, 3.74; CI, 16.44; N, 6.50;S, 7.43. Found: C, 47.54; H, 4.04; CI, 16.20; N, 6.29; S, 7.52 percent.

Fractions 32 to 43 provided 160 mg. of the cis isomer of the abovecompound, which is recrystallized from Anal. calcd. for C H C1 N O S: C,47.34; H, 3.74; C1, 16.44; N, 6.50; S, 7.43. Found: C, 47.55; H, 3.93;C1, 16.63; N, 6.31; S, 7.40 percent.

The reaction of this example is repeated using benzene dioxane,tetrahydrofuran and acetonitrile as the solvent, with the same results.

EXAMPLE 2 This example illustrates the reaction of p-nitrobenzyl6-phtha1imido-2,2-dirnethyl-penam-3-carboxy1ate with chlorine.

6Phthalimido-2,2-dimethyl-penam-3-carboxylic acid p-nitrobenzyl ester isprepared by placing a mixture of 1.0 g. of6-phtha1imido-Z,2-dimethyl-penam-3- carboxylic acid, 0.4 ml. oftriethylamine, 0.75 g. of pnitrobenzyl bromide and 10 ml. of dimethylformamide in a refrigerator for 3 hours. Thereafter, 10 ml. of water areadded and the resulting precipitate formed is filtered, washedwithacetone and recrystallized from methylethyl ketone to yield colorlesscrystals; mp 233-34C.; nmr(CDCl 89(S,3l-1); 111(S,31-1); 287(S,1H);322(S,2); 338.5(d,1H,J=4.5Hz); 342(d,1H,J=4.5Hz); 472 cps(m,8ArH).

Anal. Calcd. for C H N O S: C, 57.38; H, 3.98; N, 8.73; S, 6.60. Found:C, 57.13; H, 4.11; N, 8.53; S, 6.81 percent.

A solution of 4.81 g. (0.01 mole) of the p-nitrobenzyl ester preparedabove in 60 ml. of methylene chloride is cooled with dry ice, and 10 ml.(0.01 mole) ofa 1 M solution of chlorine in methylene chloride is addeddrop-wise over a period of about 10 minutes. The resulting mixture isthen maintained at room temperature for 50 minutes, and then the solventis evaporated and the residue dried in vacuo.

The trans-isomer is isolated as an amorphous solid by chromatographyover silica gel and is identified as pnitrobenzyl 2-chloro-a-(1-chlorothio-1-methy1ethyl)- 4-oxo-3-phthalimido-1-azetidineacetate.ir(CHCl 1800, 1785, 1750, 1730, 1400, 1352, and 1108 cm; nmr(CDCl103.5(S,6); 281(S,1); 328(S,2); 334.5 (d,1,.1=2l-lz); 367(d,l,J=2Hz);and 474 cps(m,8ArH).

Anal. Calcd. for C H Cl N O,S: C, 50.01; H, 3.47; Cl, 12.84; N, 7.61; S,5.81. Found: C, 49.80; H, 3.51; Cl, 12.79; S, 5.74 percent.

EXAMPLE 3 This example illustrates the reaction of 2,2,2- trichloroethyl6-phthalimido-2,2-dimethyl-penam-3- carboxylate with sulfuryl chloride.

2,2,2-Trich1oroethyl 6-phthalimido-2,2 dimethylpena'm-3-carboxylate isprepared by adding a solution of 1 1.6 g. (0.66 mole)of2,2,2-trichloroethylchloroformate in 50 ml. of acetonitrile dropwiseover a 15- minute period of a reaction mixture of 17.2 g. (0.05 mole) of6-phthalimido-2.2dimethyl-penam-3- carboxylic acid in 100 ml. ofdimethyl formamide and 4.8 g. (0.06 mole) of pyridine at roomtemperature.

The mixture is stirred for one hour, and then poured into 500 g. of icewater. The solid thus formed is filtered and washed with acetone. Thecrued ester (16.5 g.) is recrystallized from ethyl acetate and againfrom a mixture of methylene chloride and petroleum ether.

Analytical sample melted at 237-239; it 1824, 1785. 1775 and'l748 cm;nmr (DMSOd 93 (s, 3H); 106 (s,3H); 282 (s, 1H); 304 (s, 2H); 339(d, 1H,J=4Hz); 353 (d, 1H, J=4Hz); and 4761-12 (s, 4 arom.H). Anal. Calcd. forC H C1 N O S: C, 45.25; H, 3.16; CI, 22.76; N, 5.86; S, 6.71. Found: C,45.55; H, 3.45; CI, 22.06; N, 5.95; and S, 6.81 percent.

A mixture of 47.7 g. (0.1 mole) of the trichloroethyl ester preparedabove, 8.5 m1. of sulfuryl chloride and 1 liter of methylene chloride isstirred at room tempera ture for minutes and then refluxed for 30minutes. The solvent is then evaporated and the residue dried in vacuo.The product is then chromatographed over 200 g. of silica gel and elutedwith 2 1. of benzene, 1 liter of a mixture of benzene and ethyl acetate(95:5) and 2 1. of a mixture of benzene and ethyl acetate (90:10) inaccordance with the procedure described in Example 1.

Fractions 6 to 57 yield 24.06 g. of a mixture of the cis and transisomers (9:1) of 2,2,2-trichloroethyl 2-chloro-a-(1-chlorothio-1-methylethyl)-4-oxo-3-phthalimido-l-azetidineacetate; fractions 58 to 96 provi de 1.09 g. of amixture of the cis and trans isomers (1:1) and fractions 97 to 107provide 3.05 g. ofa mixture of the cis and trans isomers (1:9).

The latter two mixtures of cis and trans isomers (1.09 g. 3.05 g.) areagain chromatographed over 100 g. of acid-washed silica gel and elutedwith 2 l. of benzene and 2 1. a mixture of benzene and ethyl acetate(95:5). Fractions (19 m1.) 50-80 gave 0.82 g. of trans isomer; fractions(l9ml.) 81-97 gave 0.22 g. of a mixture of cis and trans (1:9);fractions (19 ml.) 98-114 gave 0.42 g. of cis isomer; fractions (19 ml.)-131 gave 0.30 g. of a mixture of cis and trans (1:1); and fractions (19ml.) 133-183 gave 0.26 g. of a mixture of cis and trans and olefiniccompound.

The cis isomer shows nmr (CDC1 signals at 102 (s, 311); 107 (s, 3H); 291(s, 1H); 297 (d, 2H,J=2Hz); 342 (cl, 1H, J=4Hz); 379 (d, 1H, J=4Hz); and472 Hz(d, 4 arom. H,J=2.5 Hz). Anal. 'calcd. for C H, =,Cl N O S: :C,39.41; H, 2.76; C1, 32.31; N, 5.11;O, 14.58; S, 5.84. Found: C, 39.27;H, 3.02; Cl, 32.56; 0, 14.72; and S, 5.68 percent.

The trans isomer shows nmr (CDCl signals at 107 (s, 6H); 282 (s, 1H);296 (d, 2H, J=1.8Hz); 334(d, 1H, J=1.8 Hz); 472Hz (d, 4 arom. H). Anal.Found: C, 39.14; H, 2.88; C1, 32.59; 0, 14.88 and S, 5.68 percent.

EXAMPLE 4 Theprocedure of Example 2 is repeated using benzyl6-phenoxyacetamido-2,2-dimethyl-penam-3- carboxylate in methylenechloride and chlorine.

The product is identified as benzyl 2-chloro-a-(1-chlorothio-1-methylethy1)-4-oxo-3- phenoxyacetamido-l-azetidineacetatein the form of a mixture of the cis and trans isomers.

EXAMPLE 5 The procedure described in Example 2 is repeated using methyl6-(2',6'-dimeth0xybenzamido)-2,2- dimethyl-penam-carboxylate inmethylene chloride and bromine.

The product is a mixture of the cis and trans isomers of methyl2-bromo-a-( 1-bromothio-l-methylethyl)-3- (2 ',6-dimethoxybenzamido)-4-oxol -azetidineacetate.

EXAMPLE 6 This example illustrates the reaction of methyl 6-phenoxyacetamido-Z,2-dimethyl-penam-3-carboxylate with sulfurylchloride.

Methyl o-phenoxyacetamido-2,2-dimethyl-penam-3- carboxylate (1.82 g.) isdissolved in 25 ml. of carbon tetrachloride and a solution of 0.4 ml. ofsulfuryl chloride in 10 ml. of carbon tetrachloride is added. Soon theexothermic reaction is noticed. The mixture is stirred under helium atroom temperature for 1 hour. The solvent is evaporated and the nmrspectrum showed that the product methyl 2-chloroa-( l chlorothiol-methylethyl)-4-oxo-3- phenoxyacetamido-l-azetidineacetate is a mixtureof cisand trans-isomer in a ratio of 1:1.

The cis-isomer shows nmr signals (CDCl at 94(s, 3H); 99 (s,3ll); 238(s,3l-l); 262 (s.lH); 271 (s,2H); 342.5 (q.1H,J=4l-Iz); 370 (d,lH,J=4Hz), and 420Hz (m, 5 arom. H).

The trans-isomer shows nmr(CDCl signals at 101 (5,6H); 238 (53H); 274(s,2H); 283 (s,lH); 290 (q.lH.J=2HZ); 353 (d,lH,J=2Hz). and 420Hz (m, 5arom. .H).

EXAMPLE 7 EXAMPLE 8 The procedure in Example 2 is repeated usingpnitrobenzyl 6-phthalimido-2,2-dimethyl-penam-3- carboxylate andbromine.

The mixture of nitrobenzyl ester and bromine in methylene chloride isstirred for one hour at 76 and 1 hour at room temperature. Afterevaporation. the product is a mixture of cisand trans-isomers (ratiol;l) of p-nitrobenzyl 2-bromo-a-(l-bromothio-lmethylethyl)-4-oxo-3phthalimido-l-azetidineacetate.

EXAMPLE 9 This example illustrates the reaction of p-nitrobenzylo-phthalimido-2,2-dimethyl penam-3-carboxylate and N-bromosuccinimide.

A mixture of p-nitrobenzyl ester (lmM), N- bromosu'ccinimide (3 mM) anda catalytical amount of benzoylperoxide was refluxed for 3 hours in amixture of methylene chloride and carbon tetrachloride (2:3). Theproduct is identified as a mixture of the cis and trans isomers ofp-nitrobenzyl-2-bromo-a-( lbromothiol -methylethyl)-4-oxo-3-phthalimidolazetidineacetate.

EXAMPLE 10 This example illustrates the reaction between pnitrobenzylo-phthalimido-2,2-dimethyl-penam-3- carboxylate with 1 mole ofl-chlorobenzotriazole.

A reaction mixture of 1 mM of p-nitrobenzyl ester and 1 mM ofl-chlorobenzotrazole in methylene chloride is stirred for 1 hour, thesolvent evaporated and the product is' transp-nitrobenzyl 2-chloro-.l(N-benzotriazolylthio-l -methylethyl)-4-oxo-3 phthalimidol-azetidincacctate.

EXAMPLE I 1 This example illustrates the reaction of methyl 6-(phenoxy-a,a-dimethylacctamido)-2.2-dimcthylpenam-3-carboxylate with .1mole of chlorine.

The starting ester was prepared by reaction of 12 g. of potassium6-(phenoxy-a,a-dimethylacctamido)-2,2- dimethylper1am-3acarboxylate with5 ml. of methyl iodide in 50 ml. of dimethylformamide for 3 hours atroom temperature. After usual work-up procedure, the oily residuecrystallized by standing at room temperature to give 10 g. of methyl6-(phenoxy-a,a-dimethylacetamido)-2,2-dimethyl-penam-3-carboxylate.

This ester (392 mg., lmM) was dissolved in 10 ml. methylene chloride anda chlorine solution (lmM) in carbon tetrachloride was added at 76,stirred for 1 hour, kept at room temperature for 1 hour and evapo rated.The nmr spectrum indicates that the product is a mixture of cis andtrans isomers (ratio 1:10) of methyl 2 chloro-a-(l-chlorothio-l-methylethyl)-4- oxo-3-(phenoxy-a,a-dimethylacetamido)-1-azetidineacetate.

EXAMPLE 12 The procedure described in Example 1 is repeated using areaction mixture of benzyl. 6-(3'-nitrobenzamido)-2,2-dimethyl-penam-3-carboxylate in carbon tetrachlorideand sulfuryl bromide.

The product is identified as a mixture of the cis and trans isomers ofbenzyl 2-bromo-a-( l-bromothio-lmethylethy1)-3-( 3-nitrobenzamido)-4-oxol azetidineacetate.

EXAMPLE 13 The example illustrates the reaction between N-bromosuccinimide and phthalimidomethyl 6-(4-trifluoromethylphenoxypropionamido)-2,2-dimethylpenam-3-carboxylate.

Using the procedure of Example 9, a sample of phthalimidomethyl 6-(4'-trifluoromethylphenoxypropionamido)-2,Z-dimethylpenam-3-carboxylate isdissolved in carbon tetrachloride, and N-bromosuccinimide is added tothe resulting solution to provide a mole ratio of the N-bromosuccinimide to ester of about L5. The reaction mixture is thenrefluxed for 2 hours in the presence of a peroxide catalyst, after whichthe solvent is evaporated.

The residue is dissolved in benzene and chromatographed over silica gelin accordance with the procedure described in Example 1. Fractionscontaining the cis and trans isomers of phthalimido methyl 2-bromoa-(l-bromothio-l-methylethyl)-4-oxo-3-(4-trifluoromethylphenoxypropionamido)- l azetidineacetate are obtained.

EXAMPLE 14 Using the procedure described in Example 1, phenacyl6-acetamido-2,2-dimethyl-penam-4-carboxylate is reacted with sulfurylchloride.

The product is phenacyl 2-chloro-a-(l-chlorothio-lmethylethyl)-3-acetamido-4-oxo-l-azetidineacetate.

EXAMPLE The procedure of Example 9 is again repeated using methyl6-propionamido-2,2-dimethyl-penam-3- carboxylate and N-bromosuccinimide.The product is methyl 2-bromo-a-(1bromo-1-methylethyl)-4-oxo-3-propionamido-l-azetidineacetate.

EXAMPLE 16 This example demonstrates the reaction between methyl6-phenylpropionamido-2,2-dimethyl-penam-3- carboxylate with acetylhypochloride.

A reaction mixture of methyl o-phenylpropionamido-2,Z-dimethyl-penam-3-carboxylate and acetyl hypochloride in chloroformis stirred at room temperature for 50 minutes. Thereafter, the solventis'evaporated, and the residue is dissolved in benzene andchromatographed over silica gel in accordance with the proceduredescribed in Example 1.

Fractions containing both the cis and trans isomer of methyl2-acetoxy-a-(l-chlorothio-l-methylethyl)-4-oxo-3-phenylpropionamido-l-azetidineacetate are obtained.

The procedure of this example is repeated using chlorine and acetic acidas a solvent for the generation of the hypochloride in situ. The sameproduct is obtained.

EXAMPLE 17 The procedure of Example 7 is repeated using pnitrobenzyl6-(4'-methylbenzamido)-2,2-dimethylpenam-3-carboxylate and propionylhypobromide.

The product is found to contain both the cis and trans isomers ofp-nitrobenzyl 2-propionoxy-a-( lbromothio-lmethylethyl)-3-(4-methylbenzamido)-4- oxo-l azetidineacetate.

EXAMPLE 18 The procedure described in Example 11 is again repeated usingbenzhydryl 6-(phenoxy-a,adimethylacetamido)-2,2-dimethyl-penam-3-carboxylate and isobutyryl hypochloride.

The product is identified as benzhydryl 2- isobutyryloxy-a-(l-chlorothio-1-methylethyl)-4-oxo3- phenoxy-a,a-dimethylacetamidolazetidineacetate.

EXAMPLE 19 The procedure of Example 7 is again repeated using2,2,2-trichloroethyl 6-phenoxyacetamido-2,2-dimethyl-penam-3-carboxylate and acetyl hypobromide.

The product is 2,2,2-trichloroethyl Z-acetoxy-a-(lbromothio-l-methylethyl)-4-oxo-3- phenoxyacetamido- 1 azetidineacetate.

EXAMPLE 20 The example illustrates the reaction of methyl-6-(2,o-dimethoxyphenylacetamido)-2,2-dimethylpenam-3-carboxylate with 1mole of chlorine.

A mixture of 120 g. of sodium 6-(2,6'-dimethoxyphenylacetamido)-2,2-dimethy1-penam-3- carboxylate, 50 ml. ofmethyl iodide and 503 ml. of dimethylformamide is stirred for 2 hours atroom temperature. After work-up, the desired methyl ester is obtained.

EXAMPLE 21 This example illustrates the reaction of methyl 2- cliloroa-(l-chlorothio-1-methylethyl)-4oxo-3- phthalimido-l-azetidineacetate withtriethylamine.

To a solution of 1.3 g. of methyl 2-chloro-a-(lchlorothio-1methylethyl)-4-oxo-3-phthalimido-1- azetidineacetate in 10ml. of methylene chloride is added a solution of 3 ml. of Et N in 7 ml.of methylene chloride. The mixture is kept at room temperature forminutes, evaporated to dryness, and the residue extracted with 20 ml. ofcarbon tetrachloride giving 630 mg. of the crude product. The residue ischromatographed over silica gel using benzene-ethyl acetate (:5) as theeluting solvent. Fraction containing 10 ml. are collected at 17 minuteintervals. Fractions 1 1-16 give a mixture of a starting material andthe desired product. Fractions 17-22 yielded 230 mg. of pure olefinicdimethyl compound as an amorphous solid which is identified asmethyla-isopropylidene-2-chloro- 4-oxo-3-phthalimido-l-azetidineacetate.nmr(CDCl 126.5(s,3H); 14l(s,H); 232.5 (s,3H); 338(d, 1H, J=2Hz), 378 (d,1H, J=2Hz) and 424.5Hz(m, 4,Arh).

Anal. calcd. for C, H, ClN O C, 56.30; H, 4.16; N, 7.72; Cl, 9.77.Found: C, 56.41; H, 4.38; Cl, 9.55; N, 7.95%.

EXAMPLE 22 This example illustrates the preparation of olefiniccompounds from penicillin esters.

3.6 g. (0.01 mole) of methyl 6-(phenoxyacetamido)- penicillanate wasdissolved in 10 ml. of methylene chloride. While the solution was cooledto 60, 25 ml. of 1M methylene chloride solution of chlorine was added.The reaction stirred for 30 minutes at 60 and for 30 minutes at roomtemperature. The solvent was removed in vacuo. The residue is, accordingto the nmr spectrum (in CDC1 pure trans isomer and shows signals at 122and 138.5 (s, 6H, olefmic(CH 228(s, Me ester); 274(q, OCH ,J=2 and 8H2);311(q, 1H, J=l.8 and 6H2); 444(m, 5 arom H); and 465 cps (d, NH, J=8.5Hz).

EXAMPLE 23 This example illustrates the reaction of p-nitrobenzyl6-phthalimido-2,2-dimethyl-penam-3 carboxylate with 2.5 mole ofchlorine.

A solution of 7.2 g. of above carboxylate in ml. of methylene chloridewas cooled to 60C. and'45 ml. of 1M solution of chlorine in methylenechloride was added, and stirred for 30 minutes at'60C and for 30 minutesat room temperature. The solution was evaporated to dryness to givetrans-p-nitrobenzyl a-isopropylidene-2chloro-4-oxo-3phthalimido- 1azetidineacetate; the nmr spectrum (CDCl signals at l29(s,31-1); 142.5(s,3H); 327(s,2H); 338(d,lH,J=l.5.HZ); 376(d,1H,J=1.5 HZ), and 475cps(m,8arom H).

EXAMPLE 24 Using the procedure described in Example 21, pnitrobenzyl2-ch1oro-a-(1-bromothio-l-methylethyl)-4-oxo-3-phenoxyacetamido-1-azetidineacetate is reacted with triethylamine at room temperature for 1 hour.

The carbon tetrachloride solvent is then removed, and the productseparated and identified as pnitrobenzyla-isopropylidene-2-chloro-4-oxo-3- phenoxy-acetamido-l-azetidineacetate.

EXAMPLE 25 The procedure of Example 21 is again repeated using phenacyl2-acetoxy-a-( 1-chlorothio-1-methy1ethyl)-4-oxo-3-propionamido-1-azetidineacetate. After removal of the phenacylgroup, the product is a-isopropylidene- 2-acetoxy-4-oxo-3-propionamido-1-azetidineacetic acid.

EXAMPLE 26 The procedure of Example 22 is repeated using bromine andtert-butyl 6-acetamido-2,2-dimethyl-penam- 4-carboxylate in a mole ratioof 2.3.

The solvent is removed from the reaction mixture, and the productrecovered in accordance with the procedure described. After removal ofthe tert-butyl group, the product is identified as a-isopropylidene-3-acetamido-2-bromo-4-oxo-l -azetidineacetic acid.

EXAMPLE 27 The procedure of Example 22 is again repeated using sulfurylchloride and benzyl6-phenoxy-a,adimethylacetamido-2,2-dimethylpenam-4-carboxylate in a moleratio of 2.5.

The product is identified as benzyl -isopropylidene-2-chloro-4-oxo-3-phenoxy-a,a-dimethylacetamido-1- azetidineacetate.

EXAMPLE 28 The procedure of Example 7 is again repeated using acetylhypochloride and methyl 6 benzamido-2,2- dimethyl-penam-4-carboxylate ina mole ratio of 3.0. The product is identified as methyla-isopropylidene-2- acetoxy-3-benzamido-4-oxo-l-azetidineacetate.

EXAMPLE 29 The procedure described in Example 10 is repeated except thatthe mole ratio of N-chlorobenzotraizole to the penicillin ester is 3.0.The product is p-nitrobenzyla-isopropylidene-2-chloro-4-oxo-3-phthalimido-1- azetidineacetate.

EXAMPLE 30 and 12Hz); 336 (d, 1H, .l=l.8 Hz); J=1.8Hz) and 472 cps(m,4H).

Anal. calcd. for C H ChN O C, 45.03; H, 2.94; Cl, 29.54; N, 5.83; O,16.66. Found: C, 45.14; H, 3.09; Cl, 29.71; N, 5.54; and O, 16.59%.

EXAMPLE 31 This example illustrates the preparation of 2,2,2-trichloroethyl a-isopropylidene-2-isopropylthio-4-oxo-3-phthalimido-l-azetidineacetate and the corresponding acid.

A mixture of 4.8 g. of trans-2,2,2-trichloroethyla-isopropylidene-Z-chloro-4-oxo-3-phthalimido-lacetidineacetate, 2.4 g.of zinc dust, and 48 ml. of isopropyl mercaptan is refluxed for minutes,cooled, and the insoluble zinc salts removed by filtration. The filtrateis acidified and extracted with ethyl acetate. The acetate phase isseparated and filtrate evaporated. The remaining solid is dissolved in50 ml. of ethyl acetate and re-extracted with sat. solution of sodiumbicarbonate, the ethyl acetate extract is washed with water, dried,(MgSO and evaporated to yield 3.89 g. of a neutral fraction which ischromatographed over 100 g. of silica gel and eluted with l l. ofbenzene, 2 l. of benzene; ethyl acetate (:5), 1 1. benzene: ethylacetate (90:10). Fractions 83-103 give 0.12 g. of a mixture of cis andtrans esters and fractions 104-121 give 0.78 g. of 2,2,2-trichloroethyla-isopropylidene-2- isopropylthio-4-oxo-3-phthalimidol -azetidineacetate: nmr(CDCl 72(s, 3H); 78(s, 3H); 131(s, 3H); 178(m, 1H);296(q, 2H, J=8 and 12); 321(d, 1H, J=2Hz); 338 (d, 1H, J=2Hz); and 472cps(m, 4H).

Anal calcd. for: C ,H Cl N O S: C, 48.53; H, 4.07; C1, 20.46; N, 5.39;O, 15.39; S, 6.17. Found: C, 48.36; H, 4.23; Cl, 20.54; N, 5.62; O,15.48; and S, 6.40%.

The acidified filtrate and sodium bicarbonate washing are combined,reacidified with cone. HCl(pH 2.5), and extracted yielding 1.09 g. of amixture of cis and trans acids. The mixture is dissolved in 3.0 ml. ofacetone and left at room temp. overnight giving mg. of colorless silkyneedles of cis-a-isopropylidene-2-isopropylthio-4-oxo-3-ptha1imido-l-azetidineacetic acid: ir(CHCl 1782,1774, 1736, 1728 and 1396 cm; n'mr(CDCl 67(d, H, J=3.5Hz); 74(d, 3H,J=3.5Hz); (s,6H); (m, 1H); 332(d, 1,] 46Hz); 347(d, 1H, J=4.6Hz);472Hz(m,4H), and 515 cps(b, 1H); pK 6.1(66 percent DMF).

Anal. calcd. for: C H N O S: C, 58.75; H, 5.19; N, 7.21 O, 20.59; S,8.25. Found: C, 59.03; H, 5.18; N, 7.23, O, 20.30 and S, 8.35 percent.

EXAMPLE 32 This example illustrates the reaction of methyla-isopropylidene-2-chloro-4-oxo-3-phthalimido-lazetidineacetate withisopropyl disulfide and zinc in acetic acid.

A mixture of 1.0 g. of trans-methyl a-isopropylidene-2-chloro-4-oxo-3-phthalimido-l-azetidineacetate, 3 g. of zinc dust, 7ml. of isopropyl disulfide and 20 ml. of acetic acid are stirred for 5hours, filtered and the filtrate evaporated. The residue was dissolvedin ethylacetate and the soultion washed with water, a sodium bicarbonatesolution, water, and dried (MgSO,). The nmr spectrum of the crudeproduct shows 4 compo nentsf cis and trans-2-isopropylthioand cis andtrans- 2-acetoxy azetidine derivatives. The mixture is separated bychromatographyover silica gel.

The cis isomer of methyl a-isopropylidene-2-isopropylthio-4-oxo-3-phthalimido-l-azetidineacetate showed nmr(CDClsignals centered at 68 (q, 6H); 139.5(s, 6H); 175 (m, 1H); 228(s, 3H);325(d, 1H, J=4Hz); 342(d, 1H, J=4Hz), and 471cps(m, 4 arom. H).

The corresponding trans isomer shows nmr(CDCl at 70(s,3H) 77(s, 3H);126(s, 3H); 138(s,3H); 175(m,lH); 230(s,3H); 320(d, 1H, J=2Hz); 332(d,1H, J=2Hz); and 471 cps(m, 4 arom. H).

The trans isomer of methyl oz-isopropylidene-Z-acetoxy-4-oxo-3-phthalimido-l -azetidine acetate shows nmr(CDCl at 127(5,6H); 138(s, 3H); 23l(s,3H); 324(d,1H, 1 21-12); 393(d, 1H, J=2Hz) and471 cps(m,4 arom H).

EXAMPLE 3 3 This example illustrates the preparation of a-3-(2-carboxybenzamido)-2-isopropylthio-4-oxo-1- azetidineacetic acid.

A solution of 200 mg. of a-isopropylidene-Z-isopropylthio-4-oxo-3-phthalimido-1 -azetidineacetic acid dissolved in 3ml. of acetone is cooled in an ice water bath and 1N sodium hydroxidesolution is added slowly to maintain the pH. at 11. After stirring for 5minutes the solution is acidified to pl-l3 with 1N HCl and extractedtwice with ethyl acetate. The extract is washed with water, dried(MgSOand evaporated in vacuo. A thin layer chromatography, developed withchloroform: acetic acid (9:1 using silica gel plate,'indicates a veryslow-moving polar diacid. The bioautographs (Bacillus subtilis andSarcina lulea) show active spots. The nmr spectrum is consistent with adiacid structure. The product shows Gram-positive biological activity bythe disc-diffusion method.

It will be understood that various changes and modifications may be madein the details of procedure, f0rmulation and use without departing fromthe spirit of the invention, especially as defined in the followingclaims.

I claim:

1. A compound having the formula wherein R is a acyl group selected fromthe group consisting of a group of the formula 0 Q-(CHM-L wherein Q isselected from the group consisting of hydrogen and one or moresubstituents selected from the group consisting of C to C alkyl, C to Calkoxy, nitro, halogen, carboxy and trifluoromethyl and n is zero or aninteger from 1 to 5; a group of the formula wherein Q and n are asdefined above; a groupof the formula wherein Q is defined above; and, agroup of the formula bromo and C to C alkanoyloxy.

phthalimidomethyl UNITED STATES PATENT UFFECE eetmmm or QEQTWN PATENTNO. 5,860,577

DATED January l r, 1975 Page 1 of 2 r |NVENTOR(S) Stjepan Kukolja.

It is certified that error appears in the above-identitied patent andthat said Letters Patent are hereby corrected as shown below: Column 1,vline "abandon" should read --a,ba.ndone i-- Column 2, line 59,Structure (IVb) should be as follows:

corm

n CH3 t CH 8 (IVb) Column T, line 66, "tetrachlorie should readtetrachloride--.

Column 8, lines t-T and :9, the word penar'm" shouldbe in quotes.

PATENT NO.

DATED INVENTOR(S) I QER'HHQTE @F January 1 -975 Page 2 Ofi 2 St jepanEiukolja It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column Column Column Column Column [SEAL] line 55, structure (XX) shouldbe as follows:

line

line

line

line

line

line

line

line

line line 65, "-S-y should read -S-Y 55, in" should read --for--.

63, "232s, 3H) should read "232 (s, 3H)--.

r, "232.5s,3H-)" should read 232.5 (s, 3H)--. 27, "mm (CDCl389" shouldread "nor (CDCl3) 89-- 58, "(0.66 mole)" should read --(0.06 mole)--.30;

insert --of-- after "2 .l.".,

"151)" should read --l:l)--.

should read --an--.

Third Day of August 1976 Arrest RUTH C. MASON 1 Nesting Officer C.MARSHALL DANN (ommrssr'nnvr uj'larents and Tradmnurks

